Image scanners are widely used for scanning documents. Image scanners are generally classified as two major types: flatbed scanners and sheetfed scanners. In the flatbed scanner, a document is firstly placed on the glass platform, and then the optical reading device is driven by a driving device (not shown) to scan the document. For a purpose of successively scanning many paper sheets at a time, an automatic paper feeder (ADF), which is usually used in the sheetfed scanner, is integrated into the flatbed scanner. Under this circumstance, the flatbed scanner having the automatic paper feeder (ADF) is capable of performing dual-mode scanning operations. For clarification, such a scanner is referred as a dual-mode scanner hereinafter. Referring to FIG. 1A and FIG. 1B, a dual-mode scanner capable of respectively scanning a single paper sheet in the flatbed scanning mode and a lot of paper sheets in the sheetfed scanning mode is illustrated.
As shown in FIG. 1A and FIG. 1B, the dual-mode scanner 1 has an optical reading device 10 similar to that used in the general flatbed scanner. During the process of performing the sheetfed scanning operation, the optical reading device 10 should be moved under the scanning window 11 such that the light emitted from the optical reading device 10 can be projected onto the scanning window 11. Therefore, it is required to reserve an additional operative space 12 for accommodating the optical reading device 10 when the dual-mode scanner 1 is operated in the sheetfed scanning mode. Likewise, the overall volume of the scanner 1 is increased.
In views of the above-described disadvantages of the prior art, the applicant keeps on carving unflaggingly to develop an improved optical reading device of a scanning apparatus according to the present invention through wholehearted experience and research.